Temperature responsive device



J. H. DERBY 1,868,136

TEMPERATURE RESPONSIVE DEVICE July 19,`1932.

Filed Mayle. 19:50 2 sheets-sheet 1 July 19, 1932. L H, DERBY 1,868,136

TEMPERATURE RESPONSIVE DEVICE Filed May 16, 1930 2 Sheets-Sheet 2Patented July 19, 1932 meer *eme-E AJoint fir. 'umani oi` scsnsnatn, NEWYoun, Assienon'ro AMERICAN Finn runnen- Tion suenan, ornnw Younis, YQ, A

i Application filed May 16,

This invention relates to a temperature re'- `sponsive deviceforclosinga circuit when `a zgiven temperature is reached'and particularlyto a device having a fusible conductor between circuitterminals, butnormally inv p edges and over the annular insulating blockssul'ated-from atleast one 'of the terminals. In the .earlier patentgranted to myself and AErnest S. Clayton, No.V 1,274,248,1 and April -11w28/,aradisclosed and claimed devicesintended for' a similar purpose,The device asconstructed :according to my said in my application SerialNo, 269,076, ,filed patent hasproved extremelyefficient andsatisfactoryior guarding against excessive temperatures: andparticularly for giving .alarm in 'case' of or incase of excessiveAtemperatures Whiclimightglead to fire.' However, itis necessary to Vusegreat care in the manufacture of these devices ingorderto -f'fgeavoid`cold flow of the fusible conductor which might eventually closethecircuit although the temperature had not exceeded Ythe given limit.Although this objection has iot interfered Awith the usefulness oit myearlier invention it is desirable to provide a more positive meansforpreventiug the cold -llow 'lof the fusible conductor., lt, isaccordingly an object of my invention to provide a temperaturevresponsive deviceiin which `thecold eo-flow' of the 4fusible element issubstantially avoided, `and/or rendered unobjectionable. OtherObJeCtsOi"my invention will be readily apparent romgthe ac companymg`description.- f

1135 f In the aCcompanying/drawings .,Fie'urel shows a cross sectionA ofa .preferred embodiment; y f Figure 2 shows a bottom elevation;',flligure 3 sliriu'sL a partial cross section nrfniliiication;VFigures@ shows across 'section .through-anfother niodiiicati'omandFigures nand 6 shew'` partial cross sections of other embodiments.

- Referring particularly to `Figures land 2,

the' device isi'ormedwrith a metallic casing preferably ofv-Monel metalcomprising abottorn section 10 and atop section llinsulated from eachyother by the annular blocks, 12 and i150 13 which are `advantageeuslymade of a phelock the device in its oonrona'ri'on or mwa-onli4`TEMPERMunn .ansronsivn DEVICE '1930. t serial No. 452,595!

vice is designed to operate;

The bottom portion 1 0 is bent up at its v 12 and 13 soas to clamptthemin place.and assembled relation. ANearthe `center thebottoin section 10is formed with a Well 14 in which iscemented an annular ring 15 ofsuitable insulating material, advantageouslyA infusible phenoliprmaldehydey resin. Within `the' Well disk of; fusibleV alloy `1.6 ispositioned and V above this is a diskl? of insulating materialadvantageouslyinfusible phenol formaldehyde, resin or `varnishedoambric. Above .this -Aand vstill partially Within the `Well formedby'thering lis a button v18 suitably loiflllonel metal orother.corrosion-resisting conductor. T This button 18 isin electricalcentactvvithithe vupper section l1 of the caslngfand-isheld in centeredrelation thereto by a pin'lQ which projects through a :hole V2O intlresection 11. The thickness of the button 18, the insulating disk 17and the vfusible disk 16. and theshape `ofthe section 11 and the-section 1Q are such as to cause l 11 tending to return to their normalshape, there will still remain nat least a thin film of the fusedconductor 16 to form a more perfect ContactA Vwith lthe bottom 10.

As Vbetter illustrated in Figures 2 and 4,

thek sections lO and 11 arel extended on op-v positasidesto form; ears21, 22, 28 `andfQl 4for connection togbinding postsV orin other suitablemanner tothe conductors Otan electricalA circuit.

ln theembodiment illustrated in Figure 1the fusible disk,16 islaterallyconlinedV by thevertical Wall of the ring and thus cold i conductor 16is fused andsqueezed out embodiment of casing might beused approximately1.593 in outside diameter and approximately .145V

button 18 is such as to permit flow of the material is substantiallyprevented.

For greater clearness of illustration the parts have been shown insomewhat exag gerated proportion on the drawings. In an my invention ayMonel metal inch thick. In this case the ring 15 is cemented into thebottom of the well 14 and a Vfusible solder disk Vapproximately .015inch in thickness is fitted closely inside the bakelite ring, andcontacts with the casing 10 at the bottom of the ywell 14. The disk 17may be made of bakelite or other phenol formaldehyde resin or resincompound or may be made of a varnished cambric and it may be of athickness between about .O20 and .O31 inch. These figures are not thelimits of satisfactory operation but are merely thedimensions used inthe preferred embodiment. The metallic button is of a thickness relatedto the shape of the casing so that when the casing is assembled asshown, it will be deformed about .015 inch from its normal shape andwill thusexert a constant tension upon the fusible disk 16. Theclearance between the peripheraly edges of the insulating disk 17 andthe' metallic ready flow of the fused conductor into Vcontact with themetallic button 18 and to avoid any binding of these elements on thesides of the ring 15. It should, however, be sufficiently narrow toassure the fused conductor rising high enough in the space to effect agood electrical contact with the metallic button 18. The disks 12 and 13in this embodiment are approximately 3/64 of an inch thick and are madeof bakelite or other similar phenol formaldehyde condensation product orcomn position thereof.

The sections 10 and 11 may advantageously be die-pressed from sheetmetal, the parts then assembled with the ring 15 cemented to the lowersection 10 and the edges of the lower section 10 of the casing may thenbe turned over the rings 12 and 13 in order to clamp the parts in theirassembled relation.

vThe whole is then advantageously covered such, for example,

with a waterproof varnish similar asv a phenol formaldehyde or otherresinous varnish.

In the embodiment illustrated in Figures 4 and 6 the pressure element(the button 18 in Figures 3 and 6) is recessed as at' 26 lcentrallyabove the insulation and the in*- sulation used should in these casesadvantageously be flexible. This recess is preferably about .005 inch indepth, its purpose being primarily to relieve the pressure on thefusible conductor about the point of perforation through theinsulation.y They depth of the recess should, however, be sufcientlysmall vso that the fused conductor in passing Ywith the walls of thewell,A

through the 'perforations will contact with the terminal at the top ofthe recess. The width of the recess should be` at least double the widthof` the annular bearing surface which surrounds it. In these cases alsoone or more centrally positioned. openings 27 through the insulation areprovided. In these embodiments the pressure resulting from thedeformation of the casing is applied to the fusible disk over an annulararea. Such cold flow as Vresults is accommodated by the central recess,the flexible insulation lifts if Ythe fusible material bulges centrallydue to the cold flow and the whole rises into the recess 26. Thus theflow of'material into the opening` through the insulating Inaterial isavoided and the device is thus protected against the giving of falsealarms due to cold flow. y

.In the modication illustrated in Figure 5,

the insulating disk 17 is molded or fittedl on the face of the metallicbutton 18 and extends slightly `beyond the edges thereof. This extendingrim ofthe insulation serves to hold the button 18 against moving intocontact which in this case are not protected by the ring 15. If any coldflow should occur the cold metal couldgnot How back over the projectingrim of insulation vand therefore could not contact with the button 18. Ihave illustrated in Figure 5 an embodiment of my invention in which thewell is formed entirely by the bottom 10. I find it more advantageous,however, to use the ring 15 since in this way a sharper corner and amore nearly perpendicular side may be made and thus any deflecting ofthe cold thoroughly voperation by which the section 10 is formed.

In Figure 6 I have illustrated another modification of the device. Inthis embodiment the'V insulating ring 13 is extended in close to thecenter so that its inner face delines the upper part of the well- TheVlower part of the well may be'defined by a depression 14 formed in thebottom'lOV as illustrated, or the bottom may be made perfectly flat andthe insulating ring 13 be made of sufficient thickness to providetherequired depth in the well. tageous to cement the ring 13 to the bottom10 inrorder to prevent any loss of the fused conductor between theinsulator 13 and the bottom 10. t

Although I have shown the recess in Figures 3, 4 and 6 in the pressurebutton 18, the insulation 17 or the fusible metal 16 may be recessedinstead. The important thing is to relieve the pressure on the fusiblemetal adjacent the openings 27. Instead of the above In'either case itis advan.

the part `14 ef the bet-tem 1o whiehferms lthe Ybottom of the well maybe dished slightly so ibleelement is confined byithe 'ring 15 and/or isaccommodated in the'recess '26. However, as soon asY the fusion point-is reached the fusible element 16 becomes fluid and readily flows intothe narrow space between thevldisk 17 and the ring 15 or through theopening 27 and `overthe top of the disk 17 into contact with the button18. The result of-this is the closing of the circuit `through thesections 10 and ll and the automatic operation thereby of a suitablealarmor of any other de sired electrical device.

Although I have illustrated in the accompanying drawings and describedabove a preferred embodiment and a number of modifications thereof, itwill be understood that my invention is not limited to these butthatmany other changes and modifications may be madewithin the scope ofmy'invention.

Although I have referred above and inthe accompanying claims to a button`18, it is to be understood that I do not intend by this term to belimited to a button separate from the top 11, or other forms of circuitterminal with which it may be associated, but, on the contrary, thebutton thus referred to may be an integral part of the top 11 and/orthecircuit terminal as, for example, in the embodiment illustrated inFigure 4.

I have used the term floating disc in the accompanying claims to definea disc which is free to move within the well Without flexing,-2-forexample, a disc such as that shown at 17 in Figs. 1, 3, 5 and 6, asdistinguished from the. insulating disc 17 of lFig. 4.

What is claimed as new is:

l. A temperature responsive device for closing an electrical circuitwhen a given temperature is reached Vwhich comprises a circuit terminalhaving a well thereon, a conductor adapted to fuse at the giventemperature mounted in said well so that in its fused condition itv willcontact with said circuit terf minal, a layer of insulating materialsubstantially covering said fusible conductor but leaving a small spacethrough which the conductor may, when fused, flow past said insulatinglayer, a second circuit terminal resiliently pressed against theinsulating layer and toward the fusible conductor whereby to force thelatter, when fused, through said space and into Contact with said secondcircuit terminal, the second circuit terminal being recessed about saidspace whereby to avoid contact between the fusible conductor and thesecond circuit terminal in case of cold flow of the fusible conductor.

2. VA Yftemperature. responsive i device :fer -elosinganelectricalcircuit when ag'iventem when fused it will bein-centaetwith-said eir-lfcuit terminah-fa'disl-of insulating material fitted in said wellbutadfapted t'ovp'ermit` a `substantial'stream oflthe fusible conductorwhen fused to escape pustit, meansfor maintaining a resilient'pressureen said 'disk` against sai-d -fusibleconduc'tor, vand avsecoild l4circuit terminal mounted so as to contact with the fused conductor whenit escapespast the insulating disk. a

3. A temperature responsive deviee'fffor closing an electrical `circuitwhen a given temperature is reached, which comprises'acir- AcuitYterminal having a well thereon so 'that a contact portion is `withinsaid 'vv"ell,-acon` ductor adapted to fuse at the giventemperaturemounted in'said''well-so,thatwhen` fused, it will be in electricalcontact vwith thefcir- `cuit terminal, and a floating disc'in said wellof a diameter'to'leave suflicientclearancebetween its edge and the sidesof the-wll Vto permit freemovement of'said disc in the r4Well when thefusible conductor is fused, means for pressing the discagainst said'fused conductor so as to cause thelatterfwhenit is fused, to iiow past'vthedi'sc,` vand a-second circuit terminal Contact portieri'Velectrically insulated from theI first circuit terminal',fbut positionednear'the fusible conductorin said well so as to makeelectricalcontactwith the fused conductor which escapespastsa-id disc.

4. A temperature responsive device as delined in claim 3, in which thewell `is designed to limit cold flow of thegfusible conductor.V

5. "A temperature responsive'device as-de- `finedin claim 1, in-whch't-he resilient lpressure of the second circuit-terminalfis 'such"that it will/not move the insulating layer .toward the4 rst circuitterminal fartherffthan `willlea-ve a substantial layer-'of `thefzfusidconductor therebetween.

f' 6.`-A Vtemperature 'responsive device as de-l lfined'in claim Sinwhichfthesurface bf the `second circuit terminal isset back fronithecorresponding surfaceof l'fthe disk ladiacent Y the spaceithroi-igh`which thefusible metall :is to flow soas to `avoidelectrical#Contactbetween `said circuit terminal land t-he'fl`1sib`le conductor bv celdnowof the latter.-

" 7.A temperature responsive deviceffo'r closingfan electricalcircuitwhen a' lgiventemperatureisreached which' comprises a pair of circuitterminals, a conductor-adaptedjto fuset at :the given-temperaturemounted-en 'one circuit terminal vso as'to bein electrical contacttherewith when fused and-'confined so that, when'fused,"it` isfree*toff'ivv' only l So-as to contact withthe Vother circuitlten minal,insulating means separatingthe'fusic -andhaving a depression .tor mayswell the central par yble conductor from the second terminal but.having centrally disposed openings therethrough to permit escape ofsaid conductor,

when fused, into Contact withthe seco-nd tei minal, said second terminalbeing' resiliently 4pressed against saidinsulating means toward saidfusible conductor over an annular area surrounding said centrallydisposed opening adjacent said openthe fusible ,cond-uct of the fusibleconductor without causing itto flow into coning whereby ycold flow v oftact with the second circuit terminal.

8. In a t-herinostatic .circuit closer, a circuit terminal, a disk ofconducting material fusible at the desired temperature of operationofthe thermostat and having one face bearing against said terminal,insulation peripherally confining said disk, other insulation bearingagainst the remote face of said temperature of operation of thethermostat rest-ing upon said circuit terminal. and confined by thesides of said well, a second circuit terminal comprising buttonextending .intoz saidwell and having sufficient clearance therefrom tobe freely movable thc-win and insulation pressed by said button aga nstsaid fusible disk and `periplierally s iced from the sides of said wall.

10. A thermostatic circuit closer comprising a circuit terminal havingone face` ex- Osed 1 for receiving the oneratino' heat a' 2D .L t3 7disk ofaconducting material fusible at the desired operating temperaturebearing against `the other face of said terminal, insulation closelyconfining said disk above the circuit terminal Yand foimingfa wellthereabove, a second circuit terminal comprising a.- button extendinginto said well and having sufficient clearance therefrom to be freelymovable therein and insulation pressed by said button against saidfusible disk and peripherally spaced from the 11. A thermostatic circuitclosercomprising a disk'of conducting material fusible at thev desiredoperating temperature, a circuit terminal having. one face exposed-tothe Operating heat and the vother face in engage ment with said disk,rigid insulation peripherally confining saidv disk and forming I a guideextending beyond the other face of said disk, a second circuit terminalmovable within .said guideand having its face insulated .from the faceof saiddisk, said circuit ininals, said parts being adapted and relatedsidesv of said well.

terminals being so pressed toward and insulated from .each other thatsaid disk ismaintained under compression, space being provided in theinsulation between the last mentioned terminal and the fusible disk forflow of conducting material into circuit closing Contact with saidterminal when said disk is fused. Y l

12. A temperature responsive device comprising a pair of circuitterminals resiliently pressed toward each other, onek of said terminalshaving thereover means for laterally confining a fusible conductor whenfused, a fusible conductorbetween said terminals and within saidconfining means, means for insu-` lating one of said terminals from theother and from the .fusible conductor adapted to permit said conductor,when fused, to flow into circuit-closing Contact between said terso asto prevent cold lflow of the fusible con ductor into circuit closingcontact.

13.A device as ldefined in claim 12 in which the insulating means has acentral opening therethrough adapted to permit flow of the fusedconductor into contact with second conductor, and one'of the enumeratedmembers is recessed over an area surrounding said opening so assubstantially to relieve the fusible conductor adjacent the opening frompressure exerted upon the fusible conductor.

lfl. A device as defined in claim 12 in which the means for preventingcold flow comprises an annular ring surroundingtlie. fusible conductorandhaving its inner wall substantially perpendicular tothe plane of thenormal cold flow of said conductor.

'Signed at New York, N. Y.,this12th day of May, 1930'.

JOHN iLnnRBY.

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